/*
 * Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 *
 */


package javax.print.attribute;

import java.io.Serializable;
import java.util.Locale;

/**
 * Class TextSyntax is an abstract base class providing the common
 * implementation of all attributes whose value is a string. The text attribute
 * includes a locale to indicate the natural language. Thus, a text attribute
 * always represents a localized string. Once constructed, a text attribute's
 * value is immutable.
 * <P>
 *
 * @author David Mendenhall
 * @author Alan Kaminsky
 */
public abstract class TextSyntax implements Serializable, Cloneable {

  private static final long serialVersionUID = -8130648736378144102L;

  /**
   * String value of this text attribute.
   *
   * @serial
   */
  private String value;

  /**
   * Locale of this text attribute.
   *
   * @serial
   */
  private Locale locale;

  /**
   * Constructs a TextAttribute with the specified string and locale.
   *
   * @param value Text string.
   * @param locale Natural language of the text string. null is interpreted to mean the default
   * locale for as returned by <code>Locale.getDefault()</code>
   * @throws NullPointerException (unchecked exception) Thrown if <CODE>value</CODE> is null.
   */
  protected TextSyntax(String value, Locale locale) {
    this.value = verify(value);
    this.locale = verify(locale);
  }

  private static String verify(String value) {
    if (value == null) {
      throw new NullPointerException(" value is null");
    }
    return value;
  }

  private static Locale verify(Locale locale) {
    if (locale == null) {
      return Locale.getDefault();
    }
    return locale;
  }

  /**
   * Returns this text attribute's text string.
   *
   * @return the text string.
   */
  public String getValue() {
    return value;
  }

  /**
   * Returns this text attribute's text string's natural language (locale).
   *
   * @return the locale
   */
  public Locale getLocale() {
    return locale;
  }

  /**
   * Returns a hashcode for this text attribute.
   *
   * @return A hashcode value for this object.
   */
  public int hashCode() {
    return value.hashCode() ^ locale.hashCode();
  }

  /**
   * Returns whether this text attribute is equivalent to the passed in
   * object. To be equivalent, all of the following conditions must be true:
   * <OL TYPE=1>
   * <LI>
   * <CODE>object</CODE> is not null.
   * <LI>
   * <CODE>object</CODE> is an instance of class TextSyntax.
   * <LI>
   * This text attribute's underlying string and <CODE>object</CODE>'s
   * underlying string are equal.
   * <LI>
   * This text attribute's locale and <CODE>object</CODE>'s locale are
   * equal.
   * </OL>
   *
   * @param object Object to compare to.
   * @return True if <CODE>object</CODE> is equivalent to this text attribute, false otherwise.
   */
  public boolean equals(Object object) {
    return (object != null &&
        object instanceof TextSyntax &&
        this.value.equals(((TextSyntax) object).value) &&
        this.locale.equals(((TextSyntax) object).locale));
  }

  /**
   * Returns a String identifying this text attribute. The String is
   * the attribute's underlying text string.
   *
   * @return A String identifying this object.
   */
  public String toString() {
    return value;
  }

}
